Iontophoretic delivery device and method of hydrating same

ABSTRACT

A dry-state iontophoretic drug delivery device (10, 30) is provided. The device has drug and electrolyte reservoirs (15, 16) which are initially in a non-hydrated condition. In one embodiment of the invention, a sealed liquid-containing pouch (21, 22) is provided in each electrode assembly (8, 9). Water or other liquid (20) is released from the pouch (21, 22) by pulling a tab (27, 28) attached to a portion (25, 26) of the pouch (21, 22) which is capable of being torn or ripped in order to hydrate the drug and electrolyte reservoirs (15, 16) and activate the device (10, 30). In another embodiment, the device (30) is held in a package (32). The device (30) has pouches (21, 22) which release their liquid contents automatically upon removal of the device (30) from the package (32). In yet another embodiment, the device (40) is held in a package (42) having a compression zone (46). The pouches (21, 22) must be moved through the compression zone (46) when removing the device (40) from the package (42). Compression causes the pouches (21, 22) to rupture and release the hydrating liquid (20).

TECHNICAL FIELD

This invention relates to a device for delivering an agent transdermallyor transmucosally by iontophoresis. More particularly, this inventionrelates to an electrically powered iontophoretic delivery device havingelectrodes which can be hydrated or otherwise activated by the additionof liquid just before applying the device to the body.

BACKGROUND ART

Iontophoresis has in the past been defined as "the introduction, bymeans of electric current, of ions of soluble salts into the tissues ofthe body for therapeutic purposes." Iontophoretic devices for deliveringionized drugs through the skin have been known since the early 1900's.Deutsch UK Patent No. 410,009 (1934) describes an iontophoretic devicewhich overcame one of the disadvantages of such early devices, namelythat the patient needed to be immobilized near the source of electriccurrent. The Deutsch device was powered by a galvanic cell formed fromthe electrodes and the material containing the drug to be deliveredtransdermally. The galvanic cell produced the current necessary foriontophoretically delivering the drug. This device thus allowed thepatient to move around during iontophoretic drug delivery and thusimposed substantially less interference with the patient's dailyactivities.

Today, iontophoresis is not limited solely to the delivery of ions(e.g., drug ions) into the body by means of electric current. Forexample, it is now recognized that iontophoretic delivery devices can beused to deliver an uncharged drug or agent into the body. This isaccomplished by a process called electroosmosis. Electroosmosis is thetransdermal flux of a liquid solvent (e.g., the liquid solventcontaining the uncharged drug or agent) which is induced by the presenceof an electric field imposed across the skin by the donor electrode. Asused herein, the terms "iontophoresis" and "iontophoretic" refer to (1)the delivery of charged drugs or agents by electromigration, (2) thedelivery of uncharged drugs or agents by the process of electroosmosis,(3) the delivery of charged drugs or agents by the combined processes ofelectromigration and electroosmosis, and/or (4) the delivery of amixture of charged and uncharged drugs or agents by the combinedprocesses of electromigration and electroosmosis.

Recently, a number of United States patents have issued in theiontophoresis field, indicating a renewed interest in this mode of drugdelivery. For example, Vernon et al U.S. Pat. No. 3,991,755; Jacobsen etal U.S. Pat. No. 4,141,359; Wilson U.S. Pat. No. 4,398,545; and JacobsenU.S. Pat. No. 4,250,878 disclose examples of iontophoretic devices andsome applications thereof. The iontophoresis process has been found tobe useful in the transdermal administration of medicaments or drugsincluding lidocaine hydrochloride, hydrocortisone, fluoride, penicillin,dexamethasone sodium phosphate, insulin and many other drugs. Perhapsthe most common use of iontophoresis is in diagnosing cystic fibrosis bydelivering pilocarpine salts iontophoretically. The pilocarpinestimulates sweat production; the sweat is collected and analyzed for itschloride content to detect the presence of the disease.

In presently known iontophoretic devices, at least two electrodes areused. Both of these electrodes are disposed so as to be in intimateelectrical contact with some portion of the skin or other membranesurface of the body. One electrode, called the active or donorelectrode, is the electrode from which the ionic substance, medicament,drug precursor or drug is delivered into the body by iontophoresis. Theother electrode, called the counter or return electrode, serves to closethe electrical circuit through the body. In conjunction with thepatient's skin contacted by the electrodes, the circuit is completed byconnection of the electrodes to a source of electrical energy, e.g., abattery. For example, if the ionic substance to be delivered into thebody is positively charged (i.e., a cation), then the anode will be theactive electrode and the cathode will serve to complete the circuit. Ifthe ionic substance to be delivered is negatively charged (i.e., ananion), then the cathode will be the active electrode and the anode willbe the counter electrode.

Alternatively, both the anode and cathode may be used to deliver drugsof opposite charge into the body. In such a case, both electrodes areconsidered to be active or donor electrodes. For example, the anode candeliver a positively charged ionic substance into the body while thecathode can deliver a negatively charged ionic substance into the body.

Iontophoretic delivery devices generally require a reservoir or sourceof the beneficial agent to be iontophoretically delivered or introducedinto the body. Examples of such reservoirs or sources of agents includea pouch or cavity as described in the previously mentioned Jacobsen U.S.Pat. No. 4,250,878, a porous sponge or pad as disclosed in Jacobsen etal U.S. Pat. No. 4,141,359, or a pre-formed gel body as described inWebster U.S. Pat. No. 4,383,529 and Ariura et al U.S. Pat. No.4,474,570. Such drug reservoirs are electrically connected to the anodeor the cathode of an iontophoresis device to provide a fixed orrenewable source of one or more desired agents.

Iontophoretic delivery devices which are attachable at a skin surfaceand rely on electrolyte fluids to establish electrical contact with suchskin surfaces can be divided into at least two categories. The firstcategory includes those devices which are prepackaged with the liquidelectrolyte contained in the electrode receptacle. The second type ofdevice uses dry-state electrodes whose receptacles are customarilyfilled with a drug/electrolyte solution immediately prior to applicationto the body. With both types of devices, the user currently experiencesnumerous problems which make their use both inconvenient andproblematic.

With respect to the prefilled device, storage is a major concern. Manydrugs have poor stability when in solution. Accordingly, the shelf lifeof prefilled iontophoretic drug delivery devices is unacceptably short.Corrosion of the electrodes and other electrical components is also apotential problem with prefilled devices. For example, the returnelectrode assembly usually contains an electrolyte salt such as sodiumchloride which over time can cause corrosion of metallic and otherelectrically conductive materials. Another problem with prefilledelectrodes concerns maintaining the sterility of the electrodes andpreventing microbial growth therein. This is a particular problem whenthe liquid used to conduct iontophoresis is water. Althoughantimicrobial agents can be added to the drug and/or electrolytereservoirs of an iontophoretic delivery device, the addition of suchagents tends to compromise the efficiency of agent delivery. Leakage isanother serious problem with prefilled iontophoretic drug deliverydevices. Leakage of drug or electrolyte from the electrode receptaclecan result in an inoperative or defective state. Furthermore, suchprefilled devices are difficult to apply because the protective sealwhich covers the electrode opening and retains the fluid within thereceptacle cavity is must be removed prior to application on the skin.After removal of this protective seal, spillage often occurs inattempting to place the electrode on the skin. Such spillage impairs thedesired adhesive contact of the electrode to the skin and also voids aportion of the receptacle cavity. The consequent loss of drug orelectrolyte solution can disrupt electrical contact with the electrodeand otherwise disrupts the desired uniform potential gradient applied bythese devices.

Although dry-state electrodes have numerous advantages in ease ofstorage, several problems remain. For example, the drug and electrolytereceptacles of such a device are conventionally filled through anopening prior to application of the device to the patient's skin.Therefore, the same problem of spillage and loss of drug or electrolyteupon application occurs as with the prefilled electrode.

Frequently, such electrodes are not well structured to develop theproper uniform current flow required in iontophoresis applications. Suchnonuniform current flow may result from the occurrence of air pocketswithin the receptacle cavity at the skin surface. Such effects areparticularly troublesome in iontophoresis applications, where anonuniform current distribution may result in excessive skin irritationor "burning".

More recently, iontophoretic delivery devices have been developed inwhich the donor and counter electrode assemblies have a "multilaminate"construction. In these devices, the donor and counter electrodeassemblies are each formed of multiple layers of (usually) polymericmatrices. For example, Parsi U.S. Pat. No. 4,731,049 discloses a donorelectrode assembly having hydrophilic polymer based electrolytereservoir and drug reservoir layers, a skin-contacting hydrogel layer,and optionally one or more semipermeable membrane layers. In addition,Ariura et al U.S. Pat. No. 4,474,570 discloses a device wherein theelectrode assemblies include a conductive resin film electrode layer, ahydrophilic gel reservoir layer, an aluminum foil conductor layer and aninsulating backing layer.

The drug and electrolyte reservoir layers of iontophoretic deliverydevices have typically been formed of hydrophilic polymers. See forexample, Ariura et al, U.S. Pat. No. 4,474,570; Webster U.S. Pat. No.4,383,529 and Sasaki U.S. Pat. No. 4,764,164. There are several reasonsfor using hydrophilic polymers. First, water is biocompatible, highlypolar and therefore a preferred solvent for many drugs. Secondly,hydrophilic polymer components (i.e., the drug reservoir in the donorelectrode and the electrolyte reservoir in the counter electrode) can behydrated while attached to the body by absorbing water from the skin orfrom a mucosal membrane. For example, skin contacting electrodes can behydrated by absorbing sweat or water from transepidermal water loss.Similarly, electrodes attached to an oral mucosal membrane can behydrated by absorbing saliva. Once a sufficient quantity of water issorbed into the drug and electrolyte reservoirs, ions are able to movethrough the reservoirs and across the tissue, enabling the device todeliver agent to the body. Hydrogels have been particularly favored foruse as the drug reservoir matrix and electrolyte reservoir matrix iniontophoretic delivery devices, in part due to their high equilibriumwater content and their ability to absorb water from the body. Inaddition, hydrogels tend to have good biocompatibility with the skin andwith mucosal membranes. However, since many drugs and certain electrodecomponents are unstable in the presence of water, iontophoretic drugdelivery devices having a drug reservoir formed of a prehydratedhydrogel may also have an unacceptably short shelf life. One solution tothe drug stability problem is to use hydrophilic polymer drug andelectrolyte reservoirs which are in a substantially dry state, i.e., ina non-hydrated condition. The drug and/or electrolyte can for example bedry blended with the hydrophilic polymer and then cast or extruded toform a non-hydrated, though hydratable, drug or electrolyte containingreservoir. Unfortunately, the non-hydrated hydrophilic polymercomponents must first absorb sufficient quantities of water from thebody before the device can operate to deliver drug. This deliverystart-up period can take in excess of several hours. This delay makesmany devices unsuited for their intended purpose. For example, whenusing an iontophoretic delivery device to apply a local anesthetic inpreparation for a minor surgery (e.g., surgical removal of a mole), thesurgeon and the patient must wait until the drug and electrolytereservoirs of the delivery device become sufficiently hydrated beforethe anesthetic is delivered in sufficient quantities to induceanesthesia. Similar delays are encountered with other drugs.

In response to the difficulty of iontophoretic delivery of a drug whichis unstable in water, Konno et al in U.S. Pat. No. 4,842,577 disclose inFIG. 4 an iontophoretic electrode assembly having a substantiallynon-hydrated drug containing matrix and a separate water reservoir whichis initially sealed, using a foil sheet, from the drug containingportions of the electrode. In order to activate the Konno et alelectrode assembly, the top of the water reservoir container isdepressed, causing the foil sheet to break and thereby release the waterinto the non-hydrated drug-containing matrix. Unfortunately, thiselectrode design is not only difficult to manufacture but also issubject to severe handling restrictions. In particular, there is atendency for the foil seal to be inadvertently broken duringmanufacture, packaging and handling of the electrode. This can haveparticularly drastic consequences especially when the seal is brokenduring manufacture or shipping of the device. Once the seal is broken,water is wicked into the drug-containing reservoir which can causedegradation of the drug and/or other components before the device isever used.

Another disadvantage of using non-hydrated hydrophilic polymercomponents is that they have a tendency to delaminate from other partsof the electrode assembly during hydration. For example, when utilizinga drug reservoir matrix or an electrolyte reservoir matrix composed of ahydrophilic polymer, the matrix begins to swell as it absorbs water fromthe skin. In the case of hydrogels, the swelling is quite pronounced.Typically, the drug or electrolyte reservoir is in either directcontact, or contact through a thin layer of an ionically conductiveadhesive, with an electrode. Typically, the electrode is composed ofmetal (e.g., a metal foil or a thin layer of metal deposited on abacking layer) or a hydrophobic polymer containing a conductive filler(e.g., a hydrophobic polymer loaded with carbon fibers and/or metalparticles). Unlike the hydrophilic drug and electrolyte reservoirs, theelectrodes do not absorb water and do not swell. The different swellingproperties of the hydrophilic reservoir and the electrode, or theionically conductive adhesive, results in shearing along their contactsurfaces. In severe cases, the shearing can result in the complete lossof electrical contact between the electrode and the drug/electrolytereservoir resulting in an inoperable device.

DISCLOSURE OF THE INVENTION

Thus, it is an object of the present invention to provide aniontophoretic drug delivery device with electrode assemblies which aremanufactured in an initially non-hydrated or dry state but which can bequickly hydrated prior to placement on the body.

It is another object of this invention to provide an improved method ofquickly hydrating the electrode assemblies in an iontophoretic deliverydevice in order to minimize the "start-up" delay of an iontophoreticdelivery device.

It is a further object of this invention to provide an iontophoreticdrug delivery device which cannot be inadvertently hydrated prior toactual use.

It is still another object of this invention to provide an iontophoreticagent delivery device, and an "automatic" method of hydrating same,which method requires no extra effort or intervention on the part of theuser other than removing the device from its package.

These and other objects are met by an electrically powered iontophoreticagent delivery device and a method of hydrating same. The deliverydevice includes at least one dry state electrode assembly and a sourceof electrical power which is electrically connected to the electrodeassembly. The electrode assembly includes an agent reservoir comprisedof a substantially non-hydrated hydratable matrix adapted to contain theagent to be delivered. The electrode assembly is adapted to be placed inagent transmitting relation with a body surface, such as intact skin ora mucosal membrane, for electrically assisted delivery of agenttherethrough. The electrode assembly also includes an electrode inelectrical contact with both the power source and the agent reservoir.The electrode assembly has a container which contains a liquid forhydrating the substantially non-hydrated agent reservoir matrix. Atleast a portion of the container wall is comprised of a liquidimpermeable material which is broken in order to release the liquid.

In accordance with one embodiment of the invention, the liquidimpermeable material is capable of being ripped or torn. A pull tab isprovided having one portion attached to the liquid impermeable materialand another portion extending out from the electrode assembly. Pullingthe tab relative to the liquid impermeable material causes the materialto rip or tear, thereby releasing the liquid from the container. Theelectrode assembly also has liquid flow control means for directing theflow of liquid released from the container to the substantiallynon-hydrated matrix. The electrode assembly is activated (i.e.,hydrated) by pulling the tab which causes the liquid impermeablematerial to rip or tear, thereby releasing the liquid from thecontainer. The released liquid then flows into the non-hydrated matrix.

Preferably, the tab is attached to a package in which the device isheld. The tab is pulled relative to the liquid impermeable material whenthe electrode assembly is removed from the package. Thus, the action ofremoving the electrode assembly from the package "automatically"hydrates and activates the electrode assembly. Alternatively, the tab isattached to a release liner covering a skin contacting surface of theelectrode assembly. The tab is pulled relative to the liquid impermeablematerial when the release liner is removed from the electrode assembly.Thus, the action of removing the release liner "automatically" hydratesand activates the electrode assembly.

In accordance with another embodiment of the invention, the liquidimpermeable material ruptures when the pressure within the sealedcontainer reaches a predetermined level. The device is held within apackage having a compression zone therein. When the device is removedfrom the package, the sealed container is forced through the compressionzone causing the pressure within the sealed container to rise above thepredetermined level thereby causing the liquid impermeable material torupture and release the hydrating liquid.

In another embodiment, the dry state electrode assembly is provided witha sealed flexible pouch containing both a hydrating liquid and a punch.The punch has a blade which, when activated, punctures the pouch andprovides a liquid flow path from the pouch to the non-hydrated agentreservoir matrix. The blade is activated by compressing the flexiblepouch. Means are provided for preventing accidental activation of theblade by pressure inadvertently applied to the pouch.

In yet another embodiment, the dry state electrode assembly is providedwith a sealed container containing a hydrating liquid. A punch ispositioned between the container and a non-hydrated reservoir. The punchhas at least one blade which, when activated, punctures the wall of thecontainer and thereby releases the liquid from the sealed container. Thepunch has an opened structure which permits the release liquid to flowthrough the punch and into the hydratable reservoir.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side view of an iontophoretic drug delivery deviceaccording to the present invention;

FIG. 2 is a top view of the device shown in FIG. 1;

FIG. 3 is a bottom view of the device shown in FIG. 1, taken along line3--3 in FIG. 1;

FIG. 4 is a side view of a package for holding an iontophoretic deliverydevice according to one embodiment of the present invention;

FIG. 5 is a front view of the package shown in FIG. 4;

FIG. 6 is a front view of the container shown in FIGS. 4 and 5, with theiontophoretic delivery device shown in phantom;

FIG. 7 is a perspective view of the package and iontophoretic deliverydevice shown in FIGS. 4, 5 and 6, with portions of the package openedfor purposes of illustration;

FIG. 8 is a sectional view of the package and the iontophoretic deliverydevice shown in FIG. 7, taken along line 8--8 in FIG. 7;

FIG. 9 is a side sectional view of an iontophoretic delivery device anda package therefor in accordance with another embodiment of the presentinvention;

FIG. 10 is a perspective view of a fluid reservoir container, with partsshown in phantom, useful for hydrating an iontophoretic delivery devicein accordance with another embodiment of the present invention;

FIG. 11 is a side sectional view of the fluid reservoir container shownin FIG. 10, with a punch in an up or ready position, i.e., beforehydration of the underlying electrode assembly;

FIG. 12 is another side sectional view of the fluid reservoir containershown in FIGS. 10 and 11 with the punch in a down or activated positionfor hydration of the underlying electrode assembly;

FIG. 13 is a side sectional view of a fluid reservoir container andportions of an iontophoretic delivery device, with an alternative punchin a ready position, i.e., before hydration of the underlying electrodeassembly;

FIG. 14 is another side sectional view of the fluid reservoir containerand iontophoretic delivery device shown in FIG. 13, with the punch in anactivated position for hydration of the underlying electrode assembly;

FIG. 15 is a top view of the punch illustrated in FIGS. 13 and 14;

FIG. 16 is a perspective view of a package for an iontophoretic deliverydevice, with means for automatically hydrating the device upon openingof the package;

FIG. 17 is a side sectional view of the package and the device shown inFIG. 16, taken along line 17--17; and

FIG. 18 is a side sectional view of another iontophoretic drug deliverydevice according to the present invention.

In the figures, like elements are designated by the same referencenumber in the several drawings.

MODES FOR CARRYING OUT THE INVENTION

FIG. 1 is a side sectional view of an iontophoretic delivery device 10for delivering a beneficial agent through a body surface 100 such asintact skin or a mucosal membrane. Iontophoretic delivery device 10includes a donor electrode assembly 8 and a counter electrode assembly9. The donor electrode assembly 8 and the counter electrode assembly 9are separated by insulator 19. Insulator 19 prevents the electrodeassemblies 8 and 9 from short circuiting the body by preventing directelectrical and/or ion transport between the electrode assemblies 8 and 9(i.e., without current in the form of ions passing through the body).Insulator 19 can optionally be provided around the outer peripheries ofelectrode assemblies 8 and 9 (as shown in FIG. 1) to preventcontamination of reservoirs 15 and 16 by fluids such as bath water whilethe device 10 is positioned on body surface 100 (e.g., the skin).Insulator 19 is preferably formed of a hydrophobic non-conductingpolymeric material which is impermeable to both the passage of ions andwater. Preferred insulating materials include nonporous ethylene vinylacetate, polyisoprenes, polypropylenes, copolymers of isoprene andpropylene and in general any closed cell foamed plastic.

Electrode assemblies 8 and 9 are connected in series, using well knownelectrical conductors such as metal foils, wires, printed circuits orelectrically conductive films (not shown), with an electrical powersource. The power source and the electrical conductors are schematicallyshown as member 14. The power source used to power device 10 istypically one or more low voltage (e.g., 1 to 3 volt button cells)batteries. A flexible and water impermeable housing 13 covers the top ofdevice 10 including member 14 with its associated electrical components.

The donor electrode assembly 8 includes an electrode 11 and a reservoir15. The reservoir 15 contains the beneficial agent to beiontophoretically delivered by device 10. A rate controlling membranelayer (not shown) may optionally be positioned between the reservoir 15and the body surface 100 for controlling the rate at which the agent isdelivered to the body surface 100 or for limiting the delivery of agentto the body surface 100 when the device is turned off. Counter electrodeassembly 9 contacts the body surface 100 at a location spaced apart fromelectrode assembly 8. Counter electrode assembly 9 includes an electrode12 and a reservoir 16. Reservoir 16 contains an electrolyte, e.g., awater soluble electrolyte salt.

Device 10 can be adhered to the body surface 100 by means of any knownmeans for applying an iontophoretic delivery device to a body surface.For example, device 10 may be adhered to body surface 100 byion-conducting adhesive layers applied to the body-facing surfaces ofreservoirs 15 and 16. Alternatively, device 10 may be adhered to thebody surface 100 using an adhesive overlay. Any of the conventionaladhesive overlays used to secure passive transdermal delivery devices tothe skin may be used. Still further, device 10 may be adhered to bodysurface 100 through the use of tacky reservoir matrix materials forreservoirs 15 and 16 or through the use of a tacky insulator 19. Stillfurther, device 10 may be secured in ion-transmitting relation to bodysurface 100 by a strap or an elastic band, e.g., a strap or bandencircling a body part such as an arm or a leg.

When the device 10 is in storage, no current flows because the devicedoes not form a closed circuit. When the device 10 is placed on the skinor mucosal membrane of a patient and the electrode assemblies 8 and 9are sufficiently hydrated to allow ions to flow through the variouslayers of electrode assemblies 8 and 9, the circuit between theelectrodes is closed and the power source begins to deliver currentthrough the device and through the body of the patient. The donor andcounter electrode assemblies 8 and 9 normally include a strippablerelease liner, not shown, which is removed prior to application ofelectrode assemblies 8 and 9 to body surface 100.

The donor electrode assembly 8 includes an optional layer 17 of aliquid-wicking material positioned between electrode 11 and a sealedliquid-containing container or pouch 21. The wall 23 of pouch 21 isformed of a liquid-impermeable material, preferably a flexible sheetmaterial such as high density polyethylene, polypropylene or a metalfoil such as aluminum foil. Pouch 21 is sealed along the side adjacentwicking layer 17 with a liquid-impermeable material 25 which is shown inthe form of a sheet. Sheet 25 is broken, as described hereinafter, inorder to release liquid 20 from pouch 21.

Like donor electrode assembly 8, the counter electrode assembly 9 alsohas a sealed container or pouch 22 containing a liquid 20. An optionalliquid wicking layer 18 is provided between electrode 12 pouch 22. Likepouch 21, the wall 24 of pouch 22 is also formed of a liquid impermeablematerial, and preferably a flexible sheet material such as high densitypolyethylene, polypropylene or a metal foil such as aluminum foil. Theliquid 20 contained in pouches 21 and 22 is typically water, althoughother liquids including non-aqueous liquids, can also be used. Pouch 22is sealed along the side adjacent wicking layer 18 with aliquid-impermeable material 26 which is shown in the form of a sheet.Like sheet 25, sheet 26 can also be broken.

In the embodiment illustrated in FIG. 1, sheets 25 and 26 are capable ofbeing ripped or torn and preferably have a tear strength in the range ofabout 0.2 to 2.3 kg. Most preferably sheets 25 and 26 are comprised of athin, water impermeable film or foil such as polymer films, metal foils,metalized polymer films such as metal deposited on a polymer film andmetal foil/polymer film laminates. As best shown in FIGS. 1 and 3, apull tab 27 is attached to sheet 25. Similarly, a pull tab 28 isattached to sheet 26. Each of the pull tabs 27 and 28 is folded over onitself and has a graspable end portion which extends beyond theperiphery of device 10 as best shown in FIG. 2. Pull tabs 27 and 28 areattached to sheets 25 and 26, respectively, in a manner having greaterstrength than the tear strength of the material of sheets 25 and 26 sothat upon pulling, or otherwise placing tensile stress on pull tabs 27and 28, the material of sheets 25 and 26 will fail and rip or tear alongthe region where tabs 27 and 28 are attached to sheets 25 and 26. Ifnecessary, sheets 25 and 26 may be intentionally weakened in the regionswhere pull tabs 27 and 28 are attached to sheets 25 and 26,respectively, in order to ensure proper tearing of sheets 25 and 26.

The pull tabs 27 and 28 provide an important advantage not found inprior art hydratable devices. With devices such as those disclosed inKonno et al U.S. Pat. No. 4,842,577, there was a tendency for the sealbetween the water reservoir and the non-hydrated portions of theelectrode to be inadvertently broken due to accidental forces exerted onthe water reservoir during manufacture, packaging and/or handling of theelectrode. With the present design, this problem has been eliminatedsince liquid 20 is only released by the action of grasping and pullingtabs 27 and 28. The action of pulling tabs 27 and 28 requires anintentional action on the part of the user to activate (i.e., hydrate)device 10. It is much less likely that device 10 will be inadvertentlyactivated, in comparison with devices which are activated by applyingpressure on the exterior of the device in order to break a seal withinthe device. Thus, the pulling required with tabs 27 and 28 helps toprevent inadvertent hydration of the underlying electrode assemblycaused by pressure inadvertently applied to device 10. Thus, the presentdesign provides an important improvement over that disclosed by Konno etal.

In order to activate delivery device 10, reservoirs 15 and 16 (as wellas any optional ion-conducting membrane and/or adhesive layers withinelectrode assemblies 8 and 9) must become sufficiently hydrated toenable agent to be transported therethrough by iontophoresis. In orderto hydrate reservoir layers 15 and 16, as well as any optional membraneand/or adhesive layers, the liquid 20 contained in pouches 21 and 22must be released and directed to flow into the non-hydrated portions ofelectrode assemblies 8 and 9, respectively. The liquid 20 in pouch 21 isreleased by grasping and pulling pull tab 27 in the direction of thearrow shown in FIG. 1. Pulling tab 27 causes sheet 25 to tear, therebyreleasing liquid 20 into wicking layer 17. The liquid 20 is quicklyabsorbed by layer 17 and wicked across the entire top surface ofelectrode 11. Similarly, in order to hydrate the non-hydrated matrix ofreservoir layer 16, liquid 20 is released from pouch 22 by grasping andpulling tab 28 in the direction of the arrows shown in FIGS. 1 and 3.Pulling tab 28 causes sheet 26 to tear, thereby releasing liquid 20 intowicking layer 18. The liquid 20 is quickly absorbed by layer 18 andwicked across the entire top surface of electrode 12. The optionalwicking layers 17 and 18 may be comprised of liquid-wicking materialssuch as cotton, sponges, cellulose triacetate, rayon, polyesters,hydrophilic polymer resins, etc. and blends thereof. Also suitable aswicking materials are hydrophobic resin fibers, such as polypropylene orpolyester fibers which have preferably been treated to produce ahydrophilic surface, thus allowing water to adsorb to the collection offibers and be transported by capillary action with little or no waterabsorbed into the fibers themselves. Examples of hydrophobic polyesterfibers treated to produce a wettable surface, are Coolmax® and Thermax®,both sold by E.I. DuPont de Nemours and Company of Wilmington, Del.Coolmax® and Thermax® fibers, as well as wettable polypropylene fibersand other surface-wettable hydrophobic fibers, are extremely efficientwicking fibers, transporting water along the surface of the fibers andin the spaces between fibers without retaining much water within thefibers themselves.

As an alternative to wicking layers 17 and 18, the top surface ofelectrodes 11 and 12 may be provided with a plurality of liquidconveying grooves particularly in cases where electrodes 11 and 12 arecomposed of a solid polymer matrix containing a hydrophilicwater-conveying additive. As an alternative to the plurality of liquidconveying grooves, the top surface of electrodes 11 and 12 can also betextured in substantially any known manner in order to form a pluralityof small peaks and valleys of substantially any geometric configuration(e.g., a roughened surface). These small valleys convey water across theentire surface of electrodes 11 and 12.

Electrodes 11 and 12 each have a structure and/or a composition whichallows the liquid 20 to pass therethrough and into the non-hydratedreservoirs 15 and 16, respectively, as well as into any optionalmembrane and/or adhesive layers present, and thereby hydrate andactivate the electrode assemblies 8 and 9, respectively. Electrodes 11and 12 each have at least one liquid conveying pathway therethrough toallow liquid 20 released from pouches 21 and 22, respectively, to flowinto the non-hydrated matrices of reservoirs 15 and 16. For example,electrodes 11 and 12 can be formed of metal in the form of a plate (notshown) having one or more liquid conveying holes therethrough.Alternatively, electrodes 11 and 12 can be formed of a metal screen (notshown). Most preferably however, electrodes 11 and 12 are in the form ofa solid polymer matrix containing both an electrically conductive filler(e.g., carbon fibers or metal powders) and a liquid conveying additive,most preferably a hydrophilic water conveying additive.

The agent (i.e., a drug and/or an electrolyte salt) may be present inthe non-hydrated reservoirs 15 and 16 before hydration or may be addedto the non-hydrated reservoirs 15 and 16 with the liquid 20 at the timeof hydration, however in the case of an agent in the form of a drugwhich is unstable in the presence of the hydrating liquid 20, the drugis preferably present in the non-hydrated reservoir 15 before hydration.When the non-hydrated reservoir 15 already contains the agent to bedelivered, the liquid 20 preferably comprises deionized water. When thenon-hydrated reservoirs 15 and 16 initially contain no agent, the liquid20 preferably comprises an aqueous solution or suspension of a drug oran electrolyte salt. Most preferably, reservoirs 15 and 16 are eachcomprised of a hydrophilic polymer.

In most cases, the liquid 20 contained in pouches 21 and 22 will becomposed at least in part of water. However, it is well within the scopeof the present invention to "hydrate" the reservoirs 15 and 16 usingother liquids including non-aqueous liquids such as alcohols andglycols. Accordingly, as used herein, the term "hydrate" refers to therelease of either an aqueous or non-aqueous based liquid 20 from pouches21 and 22. Furthermore, in those instances where the non-hydratedreservoirs 15 and/or 16 initially contain no drug or electrolyte, thehydrating liquid 20 may comprise a liquid solution or suspension of thedrug or electrolyte. Liquid 20 may also contain other additives such aspreservatives, agents which inhibit microbial growth, and agents whichenhance the transdermal flux of drug through the skin, e.g., one or moresurfactants, and combinations of these agents. In the typical case wherethe liquid is comprised of water, the matrix of reservoirs 15 and 16will be at least partly composed of a hydrophilic material such as ahydrophilic polymer, a cellulosic sponge or pad, or other waterretaining material. Most preferably, the reservoirs 15 and 16 arecomprised of a hydrophilic polymer of the type described hereinafter.

In accordance with the present invention, at least one of electrodeassemblies 8 and 9, and preferably both electrode assemblies 8 and 9,are initially in a substantially dry state. Thus, the various iontransporting layers making up electrode assemblies 8 and 9 are initiallyin a non-hydrated condition. As used herein, the terms "dry state" and"non-hydrated" mean that the particular layer contains an insufficientamount of liquid to permit ion transport therethrough. For example, theion transmitting layers of donor electrode assembly 8 include reservoir15 and any optional adhesive and/or membrane layers. Depending upon itscomposition, electrode 11 may also be ion-conducting. For example, ifelectrode 11 is a metal foil, then it is electrically conductive (i.e.,electron conducting) but not ion-conducting. However, if electrode 11 iscomposed of a hydrophilic polymer matrix (e.g., polyvinylpyrrolidone)loaded with metal particles, then electrode 11 is also ion-conducting.In order for donor electrode assembly 8 to be considered a "dry state"electrode assembly, reservoir 15 and other ion-conducting layer(s)within electrode assembly 8 initially contain an insufficient amount ofliquid to allow efficient ion transport therethrough. Similarly, inorder for counter electrode assembly 9 to be considered a "dry state"electrode assembly, reservoir 16 and other ion-conducting layer(s)within electrode assembly 9 initially contain an insufficient amount ofliquid to allow efficient ion transport therethrough. In order to beconsidered "non-hydrated," reservoir layers 15 and 16 should initiallycontain less than about 10 wt % liquid, preferably less than about 5 wt% liquid and most preferably less than about 1 wt % liquid.

In FIGS. 4-8, there is shown an alternate embodiment of an iontophoreticagent delivery device, designated by the numeral 30, according to thepresent invention. Device 30 is held in a package 32. Pull tabs 37 and38 are attached to sheets 25 and 26, (not shown in FIGS. 4-8),respectively, in a similar manner to that shown in device 10 illustratedin FIG. 1. Sheets 25 and 26 are made of a material which is capable ofbeing ripped or torn. Pull tabs 37 and 38 (FIGS. 4-8) differ from pulltabs 27 and 28 (FIGS. 1-3) in the following respect. Pull tabs 27 and 28each have an end portion which is adapted to be grasped and pulled(relative to device 10) by the user. However, in device 30, the pulltabs 37 and 38 are not adapted to be grasped and pulled. Instead, tabs37 and 38 are attached to the package 32. As best shown in FIGS. 6 and7, the individual tabs 37 and 38 terminate in an integral tab member 39.Tab member 39 is attached (e.g., by gluing, heat sealing or bymechanical attachment, e.g., stapling) to the package 32. As best shownin FIGS. 5 and 6, package 32 has a pocket 33 within which device 30sits. Pocket 33 can be opened by unfolding closure member 34 along foldline 35. Device 30 is removed from pocket 33 by grasping device 30 andpulling in the direction of the arrows shown in FIGS. 6, 7 and 8.Because tab member 39 is attached to the package 32, removal of device30 from pocket 33 automatically causes tabs 37 and 38 to be pulledrelative to device 30, thereby ripping or tearing the liquid impermeablesheets 25 and 26 which seal the pouches 21 and 22, respectively. Thus,the dry state electrode assemblies of device 30 are automaticallyhydrated by the action of removing device 30 from package 32.

In FIG. 9, there is illustrated another embodiment of an iontophoreticagent delivery device, designated by the numeral 40, according to thepresent invention. Like the device 30 illustrated in FIGS. 4-8, device40 is also automatically hydrated upon removal from package 42. Device40, has a liquid containing pouch 21 having a flexible wall 23. Forexample, flexible wall 23 may be comprised of any liquid-impermeable,formable and flexible film or foil material and preferably is formed ofpolyethylene or polypropylene film, or soft formable aluminum foil.Pouch 21 is sealed along the side adjacent wicking layer 17 with aliquid impermeable material 45 shown in the form of a sheet. Sheet 45 isdesigned to rupture when the pressure within sealed container 21 reachesa predetermined level. For example, sheet 45 may be formed of a metalfoil and is preferably formed of brittle aluminum foil, most preferablybrittle aluminum foil which has been treated on its interior surfacewith a material which resists water induced degradation of the foiland/or which can be heat sealed with the material of wall 23.

Package 42 is composed of a relatively rigid material such as cardboard,paperboard, rigid plastics or the like. The top wall of package 42optionally has a raised portion 41 which closely accommodates the shapeof pouch 21. Alternatively, a protuberance 44 which extends into theinterior of package 42 may be provided. Package 42 has a compressionzone 46 formed by either (1) the necked-down part of portion 21 incombination with the bottom of package 42, (2) the top of package 42 andthe protuberance 44, or (3) a combination of (1) and (2) above. Thoseskilled in the art will readily appreciated that portion 41 andprotuberance 44, either alone or in combination, may be used to formcompression zone 46. Many additional configurations to package 42 forforming compression zone 46 will be obvious in light of the teachingsherein. During storage of device 40 within package 42, pouch 21 islocated outside of the compression zone 46. The compression zone 46 islocated between the "stored" position of pouch 21 within package 42 andthe opening 43 to package 42.

In order to activate device 40, device 40 is slid out of package 42 inthe direction of the arrow, forcing pouch 21 into the compression zone46. When pouch 21 encounters compression zone 46, the pouch is squeezedthereby increasing the pressure within pouch 21 to a level at least asgreat as the predetermined level, thereby causing sheet 45 to rupture.Once ruptured, the liquid 20 within pouch 21 is released into theoptional wicking layer 17 and through electrode 11 into the non-hydratedmatrix of reservoir 15 similar to device 10. In addition to the dryagent reservoir 15, device 40 also includes a non-hydrated layer 47 ofan ion-conducting adhesive. A release liner 48 is provided on the bottomsurface of device 40 and is adapted to be removed prior to placement ofdevice 40 on the body surface.

In FIGS. 10-12, there is illustrated another embodiment of aliquid-containing container in the form of a pouch used for hydrating anon-hydrated reservoir matrix in an iontophoretic delivery device. InFIG. 10, there is illustrated a sealed pouch 50 which contains ahydrating liquid 20. The wall of pouch 50 is formed of flexible sheetmaterial such as polyethylene, polypropylene or a polyester/foillaminate such as Medpar® sold by the Minnesota Mining and ManufacturingCo. of St. Paul, Minn. Positioned within pouch 50 is a punch 60. InFIGS. 10 and 11, punch 60 is in the up or ready position whereas in FIG.12, punch 60 is shown in the down or activated position. Alternatively,two or more punches 60 may be positioned within pouch 50.

Referring now to FIG. 11, punch 60 is comprised of a plunger 62 and astand 64. Plunger 62 has a blade 63 with a "+" shaped cross-section.Surrounding blade 63 are a plurality of spaced prongs 66, each prong 66having a pair of spaced raised ridges 67 and 68. Stand 64 has an annularshape with slots 61 which permit liquid 20 to flow into the hole createdby blade 63, as shown by the fluid flow arrow in FIG. 12. Stand 64 alsohas an inwardly projecting lip 65. Lip 65 is shaped to engage prongs 66with the lip 65 positioned between ridges 67 and 68 as shown in FIG. 11.Blade 63 may be made of any rigid material having sufficient strength topuncture the wall of pouch 50 when the top of pouch 50 is compressed asshown by the arrow in FIG. 12. Preferably, punch 60 is composed of arigid polymer material such as polycarbonate, polysulfone or rigidpolyvinyl chloride. As plunger 62 is pushed into stand 64, ridge 67 issqueezed past lip 65. Eventually blade 63 cuts through the bottom wallof pouch 50, and penetrates through various upper layers in theiontophoretic delivery device with the point of blade 63 ending withinwicking material 17 as best shown in FIG. 12. Liquid within pouch 50flows through slots 61 and along the open areas of the "+" shapedcross-section of blade 63 and into optional wicking layer 17, whichwicks the liquid across the upper surface of non-hydrated reservoir 15.

A dry state iontophoretic delivery device having one or moreliquid-containing pouches 50 may be used in conjunction with a packageof the type illustrated in FIG. 9 and having a compression zone 46. Thedevice can be held in the package with the pouch(es) 50 located outsidecompression zone 46. When the device is removed from the package, thepouch 50 is forced through compression zone 46 causing flexible pouch 50to be compressed, thereby activating punch 60 by pushing plunger 62 intostand 64.

Alternatively, punch 60 can be activated by having the user press on thetop of pouch 50 using ordinary finger pressure.

The lip 65 in conjunction with the spaced ridges 67 and 68 provide animportant advantage not found in prior art hydratable devices. Withdevices such as those disclosed in Konno et al U.S. Pat. No. 4,842,577,there was a tendency for the seal between the water reservoir and thenon-hydrated portions of the electrode to be inadvertently broken duringmanufacture, packaging and/or handling of the electrode. With thepresent design, this problem has been eliminated since slight pressuresexerted on pouch 50 which have a tendency to push plunger 62 into stand64 are insufficient to overcome the resistance provided by theinteraction between the lip 65 and the ridge 67 thereby preventinginadvertent hydration of the underlying electrode assembly caused bypressure inadvertently applied to pouch 50. Thus, the present designprovides an important improvement over that disclosed by Konno et al.

In FIGS. 13-14, there is illustrated another embodiment of aliquid-containing container in the form of a pouch used for hydrating anon-hydrated reservoir matrix in an iontophoretic delivery device. InFIG. 13, there is illustrated a sealed pouch 50 which contains ahydrating liquid 20. The wall of pouch 50 is formed of flexible sheetmaterial such as polyethylene, polypropylene, or a polyester/foillaminate such as Medpar®. Positioned underneath pouch 50 is a punch 70.In FIG. 13, punch 70 is in a ready position whereas in FIG. 14, punch 70is shown in an activated position. A top view of punch 70 is shown inFIG. 15 whereas the view of punch 70 illustrated in FIG. 13 is takenalong lines XIII--XIII in FIG. 15. Punch 70 is comprised of aring-shaped member 71 having a plurality (e.g., four) biased blades 72,73, 74 and 75, each of which extends radially inwardly from member 71.The member 71 and the blades 72, 73, 74 and 75 may be formed of a singleintegral member, or alternatively, the blades 72, 73, 74 and 75 can beseparately formed and then later attached by appropriate means to member71. For example, member 71, and blades 72, 73, 74 and 75 may be formedof metal and the blades may be attached, e.g. by welding, to member 71.Alternatively, punch 70 may be formed by a metal stamping operation.Still alternatively, the member 71 and the blades 72, 73, 74 and 75 canbe a single integral piece formed e.g., by molding an appropriatepolymer such as an ABS copolymer, a polyamide, or nylon.

As best shown in FIG. 13, each of the blades 72-75 has a plurality ofbends 76-78 therein. Bend 78 is substantially less flexible than bends76 and 77 and accordingly, bends 78 do not straighten out when downwardpressure is applied to the top of blades 72-75. Further, each of theblades has a free end which is oriented generally in a directionpointing towards the bottom of pouch 50. When pressure is applied to thetop of pouch 50 as shown by the arrow in FIG. 14, the pouch 50 is forceddownwardly against blades 72, 73, 74 and 75. This downward pressurecauses the more flexible bends 76 and 77 in blades 72 and 73 tostraighten, forcing the blades 72-75 into the configuration shown inFIG. 14. As will be readily appreciated, the natural bias of the blades72-75 causes their free ends (which are preferably sharpened to enhancetheir ability to puncture through backing layer 52 and pouch 50) toextend upwardly eventually puncturing backing layer 52 and the bottomwall of pouch 50, forming a hole 51 therethrough. Once hole 51 isformed, liquid 20 within pouch 50 flows out of the pouch 50, throughhole 51, through the open base of ring-shaped member 71, and into thewicking layer 17. The hydrating liquid 20 flows through the electrodelayer 11 and into the non-hydrated agent reservoir 15.

A dry state iontophoretic delivery device having a liqui-containingpouch 50 and a punch 70 may be used in conjunction with a package of thetype illustrated in FIG. 9 and having a compression zone 46. The devicecan be held in the package with the pouch located outside compressionzone 46. When the device is removed from the package, the pouch 50 isforced through compression zone 46 causing flexible pouch 50 to becompressed, thereby activating punch 70 by forcing blades 72-75 topuncture the underside of pouch 50. Alternatively, punch 70 can beactivated by having the user press on the top of pouch 50 using ordinaryfinger pressure prior to using the device.

In FIGS. 16 and 17 there is shown another iontophoretic delivery device80 which is automatically hydrated upon removal from its package 90.Package 90 is comprised of a tray 92 and a lid 94. Lid 94 is providedwith openings 95-99. The tray 92 is provided with four slots 93. Twostrips 81 and 82 are provided in lid 94 as shown in FIG. 16. Strip 81has two ends, each of which engages a slot 93. Similarly, strip 82 hastwo ends, each of which engages other slots 93 in tray 92 (not shown inFIG. 16). Strip 81 is threaded through openings 96 and 97 and passesacross opening 95 above pouch 50 by way of slots 88. Similarly, strip 82is threaded through openings 98 and 99 and passes across opening 95above a second pouch 50 by way of slots 89.

In a stored condition, the ends of strips 81 and 82 extend into slots93, thereby securing lid 94 within tray 92.

In order to remove lid 94, the strips 81 and 82 must be depressed in theregion of opening 95 as best shown in FIG. 17. Depression of strips 81and 82 causes the strips to withdraw from at least two of the slots 93located on the same side of tray 92, and preferably causes the strips towithdraw from all four slots 93 on both sides of tray 92, as best shownby the arrow in FIG. 16. In addition, depression of strips 81 and 82 inthe region of opening 95 causes pressure to be exerted on pouches 50,which causes pouches 50 to break and release water to the non-hydratedportions of device 80 in a manner consistent with that disclosed earlierherein. As will be appreciated by those skilled in the art, package 90provides a means for automatically hydrating device 80 upon removal ofdevice 80 from package 90.

In FIG. 18 there is shown another iontophoretic delivery device 110.Device 110, like device 10 shown in FIG. 1, includes a non-hydrateddonor electrode assembly 8 and a non-hydrated counter electrode assembly9. Covering the skin contacting surfaces of donor electrode assembly 8and counter electrode assembly 9 are release liners 112 and 113,respectively. Release liners 112 and 113 are typically comprised of asiliconized polyester material. One end of release liner 112 is fixedlyattached to tab 27. Release liner 112 and tab 27 are attached to oneanother using conventional means (not shown) such as gluing, stapling,etc, in the region designated 114. Similarly, release liner 113 isattached to tab 28 in the region 115 using conventional attachmentmeans. Before use, the patient or physician peels the release liners112,113 off the surfaces of electrode assemblies 8 and 9, respectively,as shown by the arrows. Once the release liners 112 and 113 are peeledaway from the skin contacting surfaces of the electrode assemblies 8 and9, the patient or physician further pulls the release liners outwardlyfrom device 110, causing tabs 27 and 28 to be pulled relative to pouches21 and 22, respectively. This pulling action operates to both open thewater containing pouches 21 and 22 in a similar manner to that describedin connection with device 10 shown in FIG. 1 and also removes therelease liners 112 and 113. This configuration assures that theelectrode assemblies 8 and 9 are hydrated, and thus device 110 isactivated, prior to placement on the body since the release liners 112and 113 must first be removed before the device 110 can be secured inplace on the body surface.

When used in connection with the reservoir 15 or the donor electrodeassembly 8, the term "agent" refers to beneficial agents, and preferablyto beneficial agents such as drugs, within the class which can bedelivered through body surfaces such as skin and mucosal membranes. Mostpreferably, the beneficial agent is soluble in the liquid used to"hydrate" the donor electrode assembly 8.

The expression "drug" is intended to have a broad interpretation as anytherapeutically active substance which is delivered to a living organismto produce a desired, usually beneficial, effect. In general, thisincludes therapeutic agents in all of the major therapeutic areasincluding, but not limited to, anti-infectives such as antibiotics andantiviral agents, analgesics and analgesic combinations, anesthetics,anorexics, antiarthritics, antiasthmatic agents, anticonvulsants,antidepressants, antidiabetic agents, antidiarrheals, antihistamines,anti-inflammatory agents, antimigraine preparations, antimotion sicknesspreparations, antinauseants, antineoplastics, antiparkinsonism drugs,antipruritics, antipsychotics, antipyretics, antispasmodics, includinggastrointestinal and urinary, anticholinergics, sympathomimetrics,xanthine derivatives, cardiovascular preparations including calciumchannel blockers, beta-blockers, antiarrythmics, antihypertensives,diuretics, vasodilators, including general, coronary, peripheral andcerebral, central nervous system stimulants, cough and coldpreparations, decongestants, diagnostics, hormones, hypnotics,immunosuppressives, muscle relaxants, parasympatholytics,parasympathomimetrics, proteins, peptides, psychostimulants, sedativesand tranquilizers.

The invention is particularly useful in the controlled delivery ofpeptides, polypeptides, proteins, macromolecules and other drugs whichhave a tendency to be unstable, hydrolyzed, oxidized, denatured orotherwise degraded in the presence of the liquid, such as water,necessary to conduct iontophoresis. For example, drugs containing eitheran ester bond (i.e., steroids) or an amide bond (i.e., peptides) may behydrolyzed in water. Specific examples of drugs which can becomedegraded in the presence of water include catachols, such as apomorphineand epinephrine, salbutamol, sulfhydryls such as captopril, niphedipine,and peptides such as VIP and insulin.

Examples of other peptides and proteins which may be delivered using thedevice of the present invention include, without limitation, LHRH, LHRHanalogs such as buserelin, gonadorelin, naphrelin and leuprolide, GHRH,insulin, heparin, calcitonin, endorphin, TRH, NT-36 (chemical name:N=[[(s)-4-oxo-2-azetidinyl]carbonyl]-L-histidyl-L-prolinamide),liprecin, pituitary hormones (e.g., HGH, HMG, HCG, desmopressin acetate,etc.), follicle luteoids, αANF, growth factor releasing factor (GFRF),βMSH, somatostatin, bradykinin, somatotropin, platelet-derived growthfactor, asparaginase, bleomycin sulfate, chymopapain, cholecystokinin,chorionic gonadotropin, corticotropin (ACTH), erythropoietin,epoprostenol (platelet aggregation inhibitor), glucagon, hyaluronidase,interferon, interleukin-2, menotropins (urofollitropin (FSH) and LH),oxytocin, streptokinase, tissue plasminogen activator, urokinase,vasopressin, ACTH analogs, ANP, ANP clearance inhibitors, angiotensin IIantagonists, antidiuretic hormone agonists, antidiuretic hormoneantagonists, bradykinin antagonists, CD4, ceredase, CSF'S, enkephalins,FAB fragments, IgE peptide suppressors, IGF-1, neurotrophic factors,parathyroid hormone and agonists, parathyroid hormone antagonists,prostaglandin antagonists, pentigetide, protein C, protein S, renininhibitors, thymosin alpha-1, thrombolytics, TNF, vaccines, vasopressinantagonist analogs, alpha-1 anti-trypsin (recombinant).

When used in connection with the reservoir layer 16 and/or the counterelectrode assembly 9, the term "agent" refers to any suitablepharmacologically acceptable electrolyte salt. Preferably, theelectrolyte salt is soluble in the liquid used to "hydrate" the counterelectrode assembly 9. Suitable electrolyte salts include water solubleand biocompatible salts such as sodium chloride, alkali metal salts,alkaline earth metal salts such as chlorides, sulfates, nitrates,carbonates, phosphates, and organic salts such as ascorbates, citrates,acetates and mixtures thereof.

Electrodes 11 and 12 are electrically conductive and may be formed of ametal, or other electrically conductive material. For example,electrodes 11 and 12 may be formed of a metal foil, a metal screen ormetal deposited or painted on a suitable backing. Examples of suitablemetals include silver, zinc, silver/silver chloride, aluminum, platinum,stainless steel, gold and titanium. Alternatively, the electrodes 11 and12 may be formed of a polymer matrix containing a conductive filler suchas a metal powder, powdered graphite, carbon fibers or other knownelectrically conductive filler material. The polymer based electrodesmay be made by mixing the conductive filler in a preferably hydrophobicpolymer matrix. For example, zinc powder, silver powder, silver/silverchloride powder, powdered carbon, carbon fibers and mixtures thereof canbe mixed in a hydrophobic polymer (e.g., an ethylene vinyl acetatecopolymer) matrix, with the preferred amount of conductive filler beingwithin the range of about 30 to 90 vol % and the remainder being thehydrophobic polymer matrix.

When the electrodes 11 and 12 are positioned between the liquidcontaining pouches 21, 22 and the non-hydrated reservoirs 15, 16,respectively, the electrodes 11 and 12 should also be able to transmitthe hydrating liquid released from pouches 21 and 22, into thenon-hydrated reservoirs 15 and 16, respectively. This can beaccomplished by forming one or more liquid conducting pathways throughthe otherwise solid electrodes 11 and 12. Alternatively, the electrodes11 and 12 can be in the form of a metal screen. If the electrodes areformed of a hydrophobic polymer matrix containing a conductive filler,the matrix can be made water permeable by adding a suitable amount(e.g., 10 to 40 vol %) of a hydrophilic additive. Preferred hydrophilicadditives include the hydrophilic polymers used in the matrices ofreservoirs 15 and 16.

In the devices illustrated in the figures, the liquid containing pouches21 and 22 have been positioned on the top surfaces of the devices. Inthis position, the liquid released from the pouches 21, 22 must becontrolled to flow through the electrode layers 11 and 12, respectively.Thus, in the devices illustrated in the figures, the liquid flow controlmeans have been shown in the form of "flow through" electrodes which arepermeable to the hydrating liquid 20, optionally with a layer 17, 18 ofa wicking material which evenly distributes the flow of liquid 20 acrossthe top surfaces of electrodes 11 and 12, respectively. However, it iswell within the scope of the present invention to position the liquidcontaining pouches 21 and 22 in other locations, for example at the sideedges of the delivery devices in which case either or both of (1) the"flow through" characteristics of electrodes 11 and 12 and (2) thewicking layers 17 and 18 may be unnecessary. Those skilled in the artmay appreciate that the term "liquid flow control means" is used hereinto broadly define any means for controlling the flow of liquid releasedfrom pouches 21 and 22 into the non-hydrated portions of the device andis not limited specifically to the "flow through" electrodes and thewicking materials illustrated in the figures.

Electrodes 11 and 12 are electrically connected to the power source inlayer 14 using well known means, e.g., printed flexible circuits, metalfoils, wires or by direct contact. As an alternative to a battery as thepower source, device 10 can be powered by a galvanic couple formed bythe donor electrode 11 and counter electrode 12 being composed ofdissimilar electrochemical couples and being placed in electricalcontact with one other. Typical galvanic couple materials for deliveringa cationic agent include a zinc donor electrode 11 and a silver/silverchloride counter electrode 12. A Zn-Ag/AgCl galvanic couple provides anelectrical potential of about 1 volt.

The matrix of reservoirs 15 and 16 can be any material adapted to absorband hold a sufficient quantity of liquid therein in order to permittransport of agent therethrough by iontophoresis. For example, gauzesmade of cotton or other absorbent fabrics as well as pads and sponges,both natural and synthetic, may be used. More preferably, the matrix ofreservoirs 15 and 16 is composed, at least in part, of a hydrophilicpolymer material. Most preferably, the matrix of reservoirs 15 and 16 isa solid polymer matrix composed at least in part of a hydrophilicpolymer. Both natural and synthetic hydrophilic polymers may be used.Suitable hydrophilic polymers include copolyesters such as Hytrel® soldby DuPont de Nemours & Co. of Wilmington, Del., polyvinylpyrrolidones,polyvinyl alcohol, polyethylene oxides such as Polyox® manufactured byUnion Carbide Corp., Carbopol® manufactured by BF Goodrich of Akron,Ohio; blends of polyoxyethylene or polyethylene glycols with polyacrylicacid such as Polyox® blended with Carbopol®, polyacrylamide, Klucel®,cross-linked dextran such as Sephadex (Pharmacia Fine Chemicals, AB,Uppsala, Sweden), Water Lock® (Grain Processing Corp., Muscatine, Iowa)which is a starch-graft-poly(sodium acrylate-co-acrylamide) polymer,cellulose derivatives such as hydroxyethyl cellulose,hydroxypropylmethylcellulose, low-substituted hydroxypropylcellulose,and cross-linked Na-carboxymethylcellulose such as Ac-Di-Sol (FMC Corp.,Philadelphia, Pa.), hydrogels such as polyhydroxyethyl methacrylate(National Patent Development Corp.), natural gums, chitosan, pectin,starch, guar gum, locust bean gum, and the like, along with blendsthereof. Of these, polyvinylpyrrolidones are preferred.

Optionally, the matrix of reservoirs 15 and 16 may also contain ahydrophobic, preferably heat fusible, polymer in order to enhance thelamination of reservoir layers 15 and 16 to the adjacent layers (e.g.,insulators 26 and 27, electrodes 11 and 12 and any optional membraneand/or adhesive layers). Suitable hydrophobic polymers for use in thematrix of reservoir layers 15 and 16 include, without limitation,polyethylene, polypropylene, polyisoprenes and polyalkenes, rubbers,copolymers such as Kraton®, polyvinylacetate, ethylene vinyl acetatecopolymers, polyamides such as nylons, polyurethanes, polyvinylchloride,acrylic or methacrylic resins such as polymers of esters of acrylic ormethacrylic acid with alcohols such as n-butanol, n-pentanol,isopentanol, 2-methyl butanol, 1-methyl butanol, 1-methyl pentanol,2-methyl pentanol, 3-methyl pentanol, 2-ethyl butanol, isooctanol,n-decanol, or n-dodecanol, alone or copolymerized with ethylenicallyunsaturated monomers such as acrylic acid, methacrylic acid, acrylamide,methacrylamide, N-alkoxymethyl acrylamides, N-alkoxymethylmethacrylamides, N-tert-butylacrylamide, and itaconic acid, N-branchedalkyl maleamic acids wherein the alkyl group has 10-24 carbon atoms,glycol diacrylates, and blends thereof. Most of the above listedhydrophobic polymers are heat fusible. Of these, ethylene vinyl acetatecopolymers are preferred.

When the drug or electrolyte is present in the reservoir matrix beforehydration, blending of the drug or electrolyte with the hydrophilicpolymer matrix components can be accomplished mechanically, either bymilling, extrusion or hot melt mixing, for example. The resultingreservoir layers may then be prepared by solvent casting, extrusion orby melt processing, for example. In addition to the drug andelectrolyte, the reservoirs 15 and 16 may also contain otherconventional materials such as dyes, pigments, inert fillers, and otherexcipients.

The combined skin-contacting areas of electrode assemblies 8 and 9 canvary from less than 1 cm² to greater than 200 CM². The average device 10however, will have electrode assemblies with a combined skin-contactingarea within the range of about 5 to 50 cm².

Having thus generally described our invention and described in detailcertain preferred embodiments thereof, it will be readily apparent thatvarious modifications to the invention may be made by workers skilled inthe art without departing from the scope of this invention and which islimited only by the following claims.

We claim:
 1. A device including an electrode assembly for anelectrically powered iontophoretic agent delivery, the electrodeassembly comprising:a) a reservoir including a substantiallynon-hydrated hydratable matrix adapted to contain an agent to bedelivered through a body surface, said reservoir being electricallyconnected to a power source; b) a sealed container in fluidcommunication with the reservoir, the container containing a liquid forhydrating the substantially non-hydrated matrix, at least a portion ofthe container comprising a liquid impermeable material which is capableof being ripped or torn, the material having an inner surface which isexposed to the sealed hydrating liquid and an outer surface; and c) atab having one portion attached to the outer surface of the liquidimpermeable material without passing through said material, wherebypulling the tab relative to the liquid impermeable material causes thematerial to rip or tear and release the liquid from the container andinto the reservoir matrix.
 2. The electrode assembly of claim 1,including a release liner covering a body contacting surface of theelectrode assembly, the release liner being attached to the tab, wherebyremoval of the release liner from the electrode assembly causes the tabto be pulled relative to the liquid impermeable material.
 3. The deviceof claim 2, wherein the release liner comprises a siliconized polyestersheet.
 4. A packaged electrically powered iontophoretic agent deliverydevice having a donor electrode assembly, a counter electrode assemblyand a power source electrically connected to the donor and counterelectrode assemblies, at least one of the electrode assembliescomprising:a) a reservoir including a substantially non-hydrated,hydratable matrix adapted to contain an agent to be delivered through abody surface; and b) a sealed container in fluid communication with thereservoir, the container containing a liquid for hydrating thesubstantially non-hydrated matrix, at least a portion of the containercomprising a liquid impermeable, breakable material;wherein the deviceis held in a package before use, said package having means operativelyassociated with the liquid impermeable material whereby removal of thedevice from the package causes said means to break the liquidimpermeable material, thereby releasing the liquid from the containerand into the reservoir matrix.
 5. The device of claim 4, wherein theliquid impermeable material is capable of being ripped or torn and themeans operatively associated with the liquid impermeable materialcomprises a tab, one portion of said tab being attached to the liquidimpermeable material, another portion of the tab being attached to thepackage.
 6. The device of claim 1 or 5, wherein the liquid impermeablematerial has a tear strength in the range of about 0.2 to 2.3 kg.
 7. Thedevice of claim 4, wherein the liquid impermeable material is rupturablewhen the pressure within the container reaches a predetermined level andthe means operatively associated with the rupturable material comprisesa compression zone within the package, whereby removal of the devicefrom the package causes the container to move into the compression zoneand increase the pressure within the container to a level at least asgreat as the predetermined level.
 8. The device of claim 1 or 4, whereinthe liquid impermeable material is selected from the group consisting ofmetal foils, polymer films, metal deposited on a polymer film and metalfoil/polymer film laminates.
 9. The device of claim 1 or 4, includingliquid flow control means for directing the flow of liquid released fromthe container to the non-hydrated reservoir matrix.
 10. The device ofclaim 1 or 4, wherein the agent is unstable or becomes degraded in thepresence of the liquid.
 11. The device of claim 1 or 4 wherein theelectrode assembly is a donor electrode assembly and the agent is adrug.
 12. The device of claim 1 or 4, wherein the liquid compriseswater.
 13. The device of claim 1 or 4, wherein the liquid comprises anaqueous solution or an aqueous suspension of the drug.
 14. The device ofclaim 1 or 4, wherein the electrode assembly is a counter electrodeassembly and the agent is an electrolyte.
 15. The device of claim 1 or4, wherein the liquid comprises an aqueous solution or an aqueoussuspension of the electrolyte.
 16. The device of claim 1 or 4, includinga liquid flow control means associated with the sealed container fordirecting the flow of liquid released from the container to thenon-hydrated reservoir matrix.
 17. The device of claim 16, wherein theliquid flow control means comprises a liquid wicking material positionedbetween the sealed container and the reservoir.
 18. The device of claim16, wherein the reservoir is electrically connected to the power sourcethrough an intermediate current distributing electrode and the liquidflow control means comprises one or more liquid conveying pathwaysthrough the electrode.
 19. The device of claim 16, wherein the reservoiris electrically connected to the power source through an intermediatecurrent distributing electrode and the liquid flow control meanscomprises one or more liquid conveying grooves in a surface of theelectrode.
 20. The device of claim 1 or 4, wherein the reservoir iselectrically connected to the power source through an intermediatecurrent distributing electrode and the electrode is in the form of ametal screen.
 21. The device of claim 1 or 4, wherein the reservoir iselectrically connected to the power source through an intermediatecurrent distributing electrode and the electrode comprises a hydrophobicpolymer matrix containing an electrically conductive filler and about 10to 50 vol % of a hydrophilic water conveying additive.
 22. The device ofclaim 21, wherein the hydrophilic water conveying additive comprises ahydrophilic polymer.
 23. An electrically powered iontophoretic agentdelivery device including a donor electrode assembly, a counterelectrode assembly and a source of electrical power which iselectrically connected to the donor and counter electrode assemblies, atleast one of the donor and counter electrode assemblies comprising anelectrode assembly of claim 1 or
 4. 24. An electrically powerediontophoretic agent delivery device including a donor electrodeassembly, a counter electrode assembly and a source of electrical powerwhich is electrically connected to the donor and counter electrodeassemblies, each of the donor and counter electrode assembliescomprising an electrode assembly of claim 1 or
 4. 25. The device ofclaim 22 or 23, wherein the donor and counter electrode assemblies areseparated by an ion-impermeable separator.
 26. The device of claim 1 or4, wherein the power source comprises a battery.
 27. The device of claim1 or 4, wherein the body surface is intact skin or a mucosal membrane.